Electrical precipitation apparatus



July 25, 1944. J. H. HAMILTON ELECTRICAL PRECIPITATION APPARATUS 4 Sheets-Sheet 1 Filed July 14, 1942 w 3%, a M l .I 8 1 3 2:5... .v m I I fi w 7 ...,l w hulk w i U z h a w J v 7 a r m .T 1 r o E v. a A I 4 W r 7 2 u w y A 9 ,C 3 \T 5 L. 6% W M A m w a m 7W 6 2 .3 9 m 5w w 7 12 u 9 f 1 I 2 INVENTOR.

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Arrae/vzx Patented July 25, 1944 UNITED STATES PATENT ()FFKIE5" f g I I 2.354.451 i 1 innermost. rascrrrrs-rrou mam-res v James nun Hamilton, Burbank, Oalii., m,

to Western Precipitation Corporation, Ina Angeles, Calif., a corporation of California Application July 14,1942. Serial No; 450,89:

16Claims. ollar-7) The present invention relates generally to elec-. trical precipitation of suspended particles from gases, and more particularly to single or multiple stage precipitators of the horizontal gas flow type in which the gas flows through horiaontal ducts between or defined by parallel, longitudinaliy-extended and transversely-spaced electrode structures, of which'at least one is a collectlng electrode structure adapted to collect suspended electrlcally-charged particles and to de-v posit accumulations of such particles into a maing electrode and-a non-discharging electrode,'

and thereafter migrate toward and precipitate or collect on a non-discharging collecting electrode charged to a polarity opposite to that of the dis charging electrode. The discharging and nondischarging electrodes between which thecharging field is maintained may define or. be contained within portions of the horizontal gas ducts in which the precipitation occurs, and arehere illustratively shown in such form, or theyvmay terial-collecting chamber at the bottom of the tric field, so as substantially-to avoidionization or corona discharge at that electrode.

The present invention is applicable to single stage preclpitators, in which the electrostatic field is formed between a discharging electrode and a non-discharging collecting electrode, the particles charged by the corona discharge about the discharging electrode precipitating on the non-discharging collecting electrode, or to a two-stage or "separated-field" precipitator, in, which a charging field is formed between a discharging electrode and a non-discharging electrode, beyond which is a spatially separate and functionally distinct precipitating field formed between two non-discharging electrodes, or to multiple stage v precipitators which may be regarded as made up of two or moreserially arra ed sets oi. twostage" or separated-field electrodes.

The collectingfelectrodes may be of varioustypes,- such as vertical longitudinally-extended curtains, perforate or imperforate, or such as the pocket type disclosed, in Patent No. 2,275,001,

granted March 3,1942, to E.' Anderson. In all "such precipitators', the suspended particles debe positioned in advance of such gas ducts, for

instance as disclosed in Patent Nos 2,275,001, issued March 3, 1942, to E.- Anderson. The term "discharge electrode will be understood to designate an electrode that facilitates corona discharge, because it has a configuration that establishes a sufliciently high potential gradient: at or near itssurface to create corona discharge be-' fore there is a disruptive discharge or sparkover.

For this purpose, the discharge electrode usually takes the form of, a member of small surface.

area, such asa small diameter wire or and provided with. sharp edges orfpoints, whereby there may be created in the immediate vicinity thereof a suiliciently high electric'field intensity to cause ionization and corona discharge. The term "nondischarging electrode will be understood to designate an electrode that-minimizes or preventscorona discharge therefrom because it has a configuration that establishes a sufficiently low field concentration at or near the surface to sup-v press corona discharge at elevated potentials lower than the voltage required for disruptivedischarge or sparkover. Forthis purpose, a nondischarging electrode is usually one of extended surface area, substantially free from sharp corners or other-parts of sharp surface curvature at all portions which are located within the elecposited'on the collecting electrodes fall from time to time into a collecting chamber at the bottom of the'precipitator, aided in manyinstances by the intermittent operation of a rapping mechanism which Jars the collecting electrodes and so shakes the accumulated particles free;- Under some conditions. there may be some substantial gas ilow into and hack up out of the collecting chamber, and such gas flow may actvnotonly to carry previously collected particle baclr up out,

of said chamber,.but also to erode previously depodted on and clin in to the lower P01- .tions of the collecting electrodes. This-undesirable gas circulation into and back out-of the collecting accounts for considerable redispersion of collected particles, and considerablelossinoveralirecovery.

r The primary objector the present invention is accordingly the-provision or means forgreatly restricting the flow of gas between the main gas e and the collecting chamber of electrical precipitators of the classes mentioned.

Thisobiectis aocomplishedinaocordancewith the present-invention by blocking of! the top side ofthehopperwithaseriesoaslopingbailes whichpermitthedusttofallthrough, butgreatly restrict the circulation ofgas into and back out of the hopper. These bailles,.-which are arranged between the main gaspassage'through, the precipitator and the material collecting chamber,

provideapluralityorballlewallsdeiiningaseries of relatively narrow slots for passage into the hopper of collected particles falling from the coltypes of electrical precipitators, reference for this purpose being had to the ings, in which:

accompanying draw- 7 Fig. 1 is a longitudinal vertical section taken as indicated by broken line |l of Fig. 2, the collecting electrodes in back of the illustrated rod electrodes being omitted; Fig. 1a is an enlarged detail taken from Fig. 1, showing the manner of supporting the ends of the longitudinal members from which the pocket electrodes are suspended; Fig. 2 is a plan section taken on broken line 2-'2 of Fig. 1; Fig. -3 is a transverse section taken on line 3-3 of Fig. 1; Fig. 4 is a detail section taken on line 4.4 of Fig. 1; Fig. 5 is a detail section taken on line H of Fig. 4; Figs. 6 and 6a are detail sections taken respectively on lines 6-4 and Git-6a of Fig. 1; Fig. 7

is an enlarged detail taken from Fig. 1, showing a portion of a collecting electrode and associated baflie means; Fig. 8 is a detail taken on line 3-8 of Fig. 7; Fig. 9 is a detail taken on line 33 of Fig. 7; Fig. 10 is a longitudinal vertical section showing a modified form of the invention, being a view taken on line l0 l3 of Fig. llpFig. 11 is a plan section taken on broken line "-4! of Fig. 10; Fig. 12 is an enlarged detail taken from Fig. 10, showing part of a-collecting electrode and associated baiiie means; Fig. 13 is a section taken on line "-13 of Fig; 12; and Fig. 14 is a section taken on line l4|4 of Fig. 12.

Referring first to the form ofthe invention shown in Figs. 1 through 9, which show illustratively a multiple stage, separated-field type of precipitator, there is shown at a generally rectangular shell or housing defining a horizontal gas passage between an inlet 2| at one end and an outlet 22 at the other. The housing 23 in the particular embodiment of the invention here shown for illustration includes vertical sides 23,

a preferably hopper-shaped bottom 24 forming a material-collecting chamber 0, which is preferably equipped with a screw conveyer discharge means 25 for the collected dust, and a top comprising end sections 21 and a central section 28 which may be'removable, if desired, to permit access to be gained to the interior of the precipitator.- A pair of longitudinally-spaced transchannel members 30, near the two ends of the latter, are the upper ends of vertical members 36, typically of U-shaped cross-section. The lower ends of these U -shaped members 33 engage and are welded to transverse channel-shaped members 38, typically of a cross-section similar to members 30, extending across the housing at the dividing plane between the rectangular portion of the housing and the hopper-shaped bottom 24. These members 38 are oriented with their channels facing one another, the flanges 39 having the inturned flange portions 43 being at the bottom, and they are preferably connected to side walls l3 through brackets 33a (Fig. 3) to restrain sway longitudinally of the housing. The described'channel members 33 and 33 carry the supporting structure for the preferred pockettype collecting electrodes presently to be 'described.

In the preferred construction here illustrated, there is a plurality of collecting electrodes 43 extending longitudinally and spaced transversely of the housing, each comprising a series or row of vertical V-shaped elements 46, which are aligned and spaced from one. another in the direc- 41 back, as illustrated in Fig. -9. The upper endportions ofthe series of V-shaped elements 46 are received within V-shaped' slots 48 formed in the web 49 of a longitudinal channel-shaped member 50 (Fig. 4)' whose ends extend into the channels of the members 33 and rest on and are supported by the lower flange portions 33 thereof. The V-shaped members 36 are hung from members 50 in any suitable manner; for instance, as indicated in Figs. 4 and 5, their upper corner portions 52 may be turned over so as to engage the web of the member 30. Members III are transversely spaced at desired intervals on the members 30; for instance, rivets 53 set into and projecting upwardly from the lower flanges 33' of the members 30 may be engaged with holes 54 in the webs of the members II (see Fig. la).

The two outside rows or series of V-shaped electrode elements 46 are preferably positioned verse members 23 and 33 at each end of the housing supports the corresponding top end section 21, and the removable central panel it rests on the members 33 and abuts top end sections II,

as illustrated in Pig. 1. The ends of the trans-' I verse members 33 are shown in Fig. 3 to be supported from side walls 23 as by means of brackets 30a. and the transverse members 23 may be simi- 34,'and a flange portion 33 turned inwardly from flange 34 (1651s). The members 33 maybe of similar cross-section'and arrangedas also indicated in Fig. 1.

Engaging and welded to theundersides of the is the at relatively close spacing to the side walls 23 of the shell. To close 01! gas circulation through any space which may be left, vertical bailie strips 55 may be mounted at suitable intervals therein, as indicated in Fig. 2. v I

The material-collecting chamber C of the precipitator is blocked off from the horizontal gas passageway above by means of a plurality oi balile members 63 which, in the present illustrative embodiment of the invention, are positioned at the bottom of the longitudinal spaces or gas ducts between the transversely-spaced rows of collecting electrodes 43. In the present illustrative form, these baiiie members 33 extend between and are supportedby the two lower transverse members 33. As viewed in cross-section, baflles 33 have vertical wall portions ll which engage the vertical edgesof pocket electrode elements 43. and sloping wall-portions]! extending downwardly and outwardly from the lower edges'of wall portions I.

we: of made by the wall portions 8| and 82 preferably coming approximately at the elements 46, and hung from suitable suspension lower end of the electrode elements 86. Thus the two bailie walls 82 between each two adjacent rows.

ofcollecting electrode elements 86 converge toward one another, defining at the bottom a rela- ,tively narrow longitudinally-extending slot 63,-

which is sufficiently wide to permit downward travel of dust particles falling from the collecting electrodes, but sufliciently narrow to ofiera material restriction to circulation of gas between the horizontal gas passage above and the collecting chamber C below. The slope of the wall portions 62 is made sufllcient to prevent dust particles from piling upthereon. Preferably, principally for the purpose of stiffening the bailles, the upper edge of the vertical wall portion 8| is formed with a relatively short downwardly-bent flange portion 68, also'arranged at such an angle as not'to catch dust, and the lower edge of the 'wall portion 62 is formed with a relatively short horizontal flange portion 65, which is bent inwardly or away from the slot 68 between adjacent baflles The lower wall portions 62 of baiilesf 80 are cut away at the two ends of the baffles, leaving projecting end portions 66 of vertical dimensions such as will just be received within the channels of the members 38 (Fig. 7),

the flange portions 88 of members 38 supporting the bailies by engagement with projecting end portions 65, in the mannerv clearly illustrated in Fig. '1.

Lugs 8l, bent inwardlyfrom the wall portions 6| of baffles 80, engage the open ends of the v shaped collectingelectrode elements 86 to space the lower ends of the latter, the pressure of the flow of gas longitudinally of the precipitator being relied uponto hold the-electrode elements '86 against said lugs. 7

In order to block off thegas passagewa from the material-collection chamber at each end of the latter, and also to prevent inflow of gas into the material-collecting chamber between the baifles below transverse'member 38 at the inlet end of the. apparatus, as well as" outflow of gas from said chamber between the-battles at the discharge end of the apparatus, suitable closure means are provided;- as here typically shown, vertically-extending transverse baille plates or walls 81 are mounted on members 38 at both ends of the precipitator, extending transversely the full distancebetween the side walls of the hoppershaped bottom that forms the material-collecting chamber, and depending substantially below the level of the baflles. .Additional transverse 'bafl'les 98 may also be provided at intervals alon "the length of the hopper-and below the baffle members 88.

In the particularpreeipitator here chosen to illustrate the invention, rows of high-tension alternate discharging and non-discharging electrodes are positioned in" the longitudinally-extending spaces or gas ducts defined by the several series or rows of collecting electrode elements 46, the latter being spaced properly to accommodate these rows of discharging and non-discharging electrodes, with proper transverse spacing for the necessary electrical action. The preferred, and

here illustrated, form of high-tension electrode system'forms the subject matter of a co-pendingapplication of Harry J. White, entitled Electrical precipitation apparatus, illed July 13, 1942,

' Ser. No. 450,711. It includes a supporting structure comprising a high-tension frame 10 near each end of the housing, spaced somewhat be- .yond the ends, of the rows of collecting electrode central vertical rod 18 extending therethro ugh and on downwardly to the upper horizontal transverse frame member 14 of the frame II.

Nuts 15 threaded on the lower ends of rods 18 support the lower ends of compression springs "16, the upper ends of which support the members 14. The frames 10 are thus spring-supp rted from high-tension conducting'rods 13. Frames 18 each include two vertical end members 11,

preferably aligned with rows of pocket collecting electrode elements 46 (see'Fig. 3) so as noteto interfere with the gas passages between the rows of electrode elements 86, the upper ends of member 61 being welded to upper transverse mem bers H, and the lower ends engaging and being welded to a lower transverse member 18.

' Connected to electrode rod 13 at the upper end of one of the insulators Ii is a conductor 18, which passes through insulator 80 in the side ofbushing housing I2 and connects on the outside to electrical conductor 8|, which will be understood to be energized from one terminal, usually the negative terminal, of a suitable hightension source of unidirectional current. The precipitator housing, and therefore the pocket collecting electrode structure, are electrically grounded, as is the positive terminal of the source of current. The upper and lower transverse members'lLand 18 of high-tension frames I8 carry upwardly-projecting supporting pins 88, the upper ends of which engage and support the end portions of upper and lower longitudinally-extending rails 85 and", respectively, spaced uniformly between the rows of collecting electrode elements 46, and adapted for support of the pres-' ently-described high-tension discharging and which is mounted in a hole 88 of upper rail 88,. the top of the rail 1 ribbons and the like.

non-discharging electrodes. These rails 88 and 86 are generally of inverted U:-,shape in crosssection, with inwardly-turned flange portions-81 at the edges of the two sides, as illustrated in Fig. 6-. The tops of members-85 and 86 are provided with uniformly-spaced pairs of verticallyaligned holes 88, adapted'to receive with free sliding flt vertically-disposed non-discharging electrode rods 80 and discharging electrode elements 9 l The former may be solid rods or tubes, and will be understood tobe of sufllcien't diameter that high electrostatic field stresses at their surfaces, such as might cause ionization of the surrounding gases, will be avoided. The upper ends of the electrode' rods 90 are furnished with heads 92, adapted to engage the tops of upper rails 88,

for the purpose of support of the rods. In the case of tubular rods, these heads 92 are conveniently provided by welding rivets 88 in the upper ends of the tubes (Fig. 6).

The discharging electrode members 9| include portions having formations of relatively smallradius of curvature, such :as will establish high electrostatic stress sufllcient to cause ionization ofthe surrounding gases. Suitable known forms include fine wires, twisted square bars, twisted The form here chosen for illustrative purposes embodies a twisted ribbon 88.

The upper end of this twisted ribbon is here.

shown as welded to the lower end of a rivet,

the head of the rivet engaging for support (Fig. 6a)

. desirable ing rod electrodes 80, a'suitable spacing being provided betweenthe discharging electrodes and the non-discharging electrodes, in order to prevent shielding of the former by the latter. At

suitable points along the length of the electrode structures, additional transverse rows of discharging electrodes may be As here shown, two such additional rows are illustrated.

The discharging and non-discharging electrodes l and ii are maintained at a high, direct current potential, by reason of their connection through rails 85 and N with the high-tension frames 10. The housing structure Ill and, therefore, the pocket-type V-shaped electrodes II, are electrically grounded, as previously stated. It will be understood that an electrostatic field will be established between the electrode members mounted on the rails 85 and 86 and the adjacent V-shaped collecting electrodes 46, and that this field will be of ionizing intensity adjacent the discharging electrodes SI, and below ionizing intensity adiacent the non-discharging electrodes The dust-laden gas passing between th dis charging electrodes Si and the V-shaped 'elec-' trodes I is ionized, causing the dust particles to become electrically charged, so as to migrate toward the collecting electrode structure. .Passing beyond the charging field created by the discharging electrodes, the charged dust particles come within the influence of the precipitating field between the non-discharging electrode rods II and the V-shaped pocket electrodes 46, and continue their migration toward the latter and into the spaces between them, finally to deposit on their surfaces.

The dust particles thus received within the pooh between adjacent v-shaped electrode chamber. Re-dispersion of dust collected in the chamber and passage of such dust back up into the gas passage above is therefore materially curtailed,'as is erosion of dust particles collected on the lower portions of collecting electrode elements ll by gas flow upwardly from the chamber.

It is, of course, impossible to eliminate completely all movement of gas within the materialcollecting chamber and, for the purpose of further reducing circulation of gas within said chamtrode structure. The collecting electrode struc-- ture is again preferably of a pocket type, though here shown as of a modified design.

The housing, including the hopper-shaped bottom forming the material-collecting chamber, the complete supporting system for the high-tension electrode elements, and portions of the supporting arrangements for the pocket electrode structure, are illustratively the same as corresponding parts of the form of Figs. 1 through 9, and corresponding parts are accordingly designated by like reference numerals but with the sub-letter elements II are removed from the gas current into relatively quiescent zones, and the tendency for re-dispersion of particles depomted on the electrode elements 48 due to "erosion by the gas stream is minimized. Of course, as many transverse rows of discharging electrodes ll may be incorporated as desired, additional rows increasing the overall dust recovery, though more than two such rows in addition to the first will usually fail to increase the recovery materially.

The dust particles gathered on the surfaces of the V-shaped collecting electrodes 48 fall from time to timeyalded preferably by intermittent operation of a suitable rapping mechanism, not here illustrated, the falling dust descending partially outside the pocket electrodes and goingon down through the spaces 83 between. the outside surfaces of the sloping portions 81 of baiiles i0, and partially within the vertical-channels or passageways defined by the pocket electrodes to-pess downwardly through the spaces It between the vertical wall portions ll of the bafiles. As stated above, the sloping baiiies I materially restrict the gas circulation spaces between the horizontal a. annexedin the case of the form of Figs. 10 through 14.

Thus, a pair oi upper, generally channel-shaped transverse members 30a is provided, and. from each of said members is hung a pair of vertical members 36a, preferably U-shaped incross section, the lower ends of the latter carrying a horizontal transverse member which, however, is in this instance of angle cross-section and is designated by numeral MI. The lower ends of the members "a engage the horizontal flanges III of angle members Hill, and the members I" are so oriented that their vertical flanges I02 extend downwardly from flanges IM in the arrangement clearly illustrated in Fig. 12.

There is again a plurality of transverselyspaced rows of collecting electrode elements, here designated by numeral I, each of which, in the illustrative construction here detailed, comprises two vertically-extending members having vertical wall portions I05 positioned back to back in planes extending longitudinally of the precipitator and formed at their two vertical edges with flange portions I06 bent preferably somewhat in the direction of gas flow (see Fig. 14). The walls.

In! and flanges I6 define the protected pocketsfl' and also form channels or passageways, 'open laterally to the gas ducts, and leading downwardly "to the hopper-shaped bottom and theelectrode members III are spaced apart longas passage above and the collecting chamber 0 below, tending substantially to reduce the unnow of 8a: into and backout or said gitudinally to providevertical passages connecting adjacent gas ducts through the collecting electrode structure. Welded to theupper end portions of the two walls m member Illv are the two legs I01 .of a hanger Ill, and the hangers I08 01' each row of electrode members I are suspended by means of pins I" from a pair of horizontal and longitudinally-extending electro'de supports Hll. These supports ll: artla'weldegto the'under side of -a channelam an are. spaced a to We" '"betw part receive the of each electrode.

them. two ends of the ass-1,407

channel-beam III are received within the channel of the transverse members 30a, as shown in Fig. 12. The several channel members III may be spaced properly along transverse members 30a by means of rivets II2 set into and projecting upwardly from the lower flanges of the members a and engaging with holes H3 in the webs of the beams III. As in the previously described form of precipitator, the two outside rows of collecting electrode elements I04 are preferably positioned at relativelyv close spacing to the side walls 23a of the shell. -To close oif gas circulation through any space which may be left, vertical baiiles 45a may be mounted at suitable intervals therein, (see Fig. 11).

Positioned between the lower portions of the longitudinally-extending rows of pocket electrode members I04 are the longitudinally-extending baflie members 5, which serve to block off gas circulation-between the main gas passage through the vprecipitator and the material-collecting chamber. These-baflles I I5, one of which is thus space or gas duct between each pair of adjacent rows of collecting electrodes I04, comprise two I sloping wall portions .I I5 diverging downwardly lower portions thereof, as seen best in Fig. '13.'

provided in the lower portion of the longitudinal The end portions of these baffles H5 are'engagedportions IIO .of baffles 5 are preferably secured,

in assembly with the adjacent collecting electrode 7 elements I04 by means of long cotter pins I22, in

. a manner clearly illustrated in Fig. 13.

' above.

, The gas in the gas passageway is blocked oil. from entering and leaving the material-collecting I stantially below the level of the baflles, so as also to restrict flow of gas into'and out of the ends of the material-collecting chamber below the bames. v

The high-tension'electrodesmay, ofcourse, be the same as employed in the precipitator illustrated in Figs..1 through 9 though I have elected to illustrate the precipitator of Figs. 10,through 14 in single-stage form. Accordingly, the upper and lower electrode supporting rails 85a and 0611.

are arranged forsupport of'a plurality of suitably spaced discharging electrodes 9Ia, which in v this instance are shown in the form of headed,

of the discharging electrode lla suflicient to cause ionization of the surrounding gases. The dust-laden gas, passing through these electrostatic flelds, is ionized, causing thedust particles to become electrically charged, soas to migratetoward the collecting electrode elements I04. The charged dust particles thus travel toward and into the relatively protected spaces or pockets between the flanges I00 of the collecting electrodes, finally to deposit on the surfaces of-the flanges I00 and walls I05. The dust particles thus received within the pockets" are removed from the gas currents Into relatively quiescent zones, and the tendency for re-dispersion by erosion is minimized.

The dust particles collected on the surfaces of the pocket electrode elements I04 fall from time to time, aided preferably by intermittent operation of asuitablerapping mechanism not shown, the dust reaching the material-collecting chamher by passing through the spaces I defined by the vertical walls of the pocket electrodes and the vertical walls 8 of the baflle members H5. Any dust falling outside-the pockets of the electrode members I04 strikes the sloping walls IIG of the baflies and is guided thereby into the-vertical spaces or passageways I30 aforementioned.

The passageways for the dust particles-shaken from the collecting electrode members I04 are thus restricted tothe spaces I30, the'entirety of the space between the rows of collecting elec- Circulation of gas down into and back out of the material-collecting chamber is aecordinglyvery materially restricted. In practice, there is insufllcient such circulation to cause any great carry-back of dust from the chamber to the space Moreover, the gas circulation upwardly from the chamber is insumcient to cause serious erosion of dust from the collecting electrodes. To restrict flow longitudinally of the chamber of what little gas does enter from above, however, vertical. transverse baille plates I3I may be mounted therein, as illustrated in Fig. 10.

It will beunderstood that the drawings and description are merely illustrative of the invention, rather than restrictive thereon, and that various changes in design, structure and arrangement may be made without departing from the spirit and scope of the invention or of the appended claims.

- I claim: c

1. In an electrical precipitationjapparatus for.

removing suspended particles from a gas, the

electrodes extending longitudinally and spaced transversely of said gas passageway and defining -longitudinally-extending gas ducts, said collecttwisted square bars (see Fig. 13). These are spaced at sufflcient intervals longitudinally 'of.

the rails a and 86a to prevent electrical shielding.

It will be understood that an electrostatic field will be'established between each such discharging electrode member III a mounted. on the rails 15a and 06a and the adjacent collecting electrode elements I04, and that this field will be of very hi intensity at he sharp edgev formations ing electrodes each comprising a longitudinal row of pocket electrode elements having particle collecting surfaces defining passageways open tothe gas ducts and leading downwardly-into said chamber, and longitudinally-extending baflles at the bottoms of said gas ducts, said' bailles including baflle walls restricting the circulation of gas between said-gas ducts and'said chamber.

* 2. In an electrical precipitation apparatus for" removing suspended particles from a gas, the combination comprising; a shell enclosing a horizontal passageway for a stream of the gas, and

formed with a material-collecting chamber be-' low said horizontal gas passageway,.vertical collecting electrodes extending longitudinally and spaced transversely of said gas passageway and defining longitudinally-extending gas ducts, said collecting electrodes each comprising a longitudinal row of pocket electrode elements having particle collecting surfaces defining passageways open to the gas ducts and leading downwardly into said chamber, and a pair of horizontallyspaced, longitudinally-extending baiiies at the bottom or each of said gas ducts, the bafiies of each such pair having wall portions sloping downwardly toward one another to define relatively narrow longitudinally-extending slots for downward passage or collected material.

3. In an electrical precipitation apparatus for removing suspended particles from a gas, the combination comprising: a shell enclosing a horizontal passageway for a stream or the gas, and formed with a material-collecting chamber below said horizontal gas passageway, vertical collecting electrodes extending longitudinally and spaced transversely of said gas passageway and defining longitudinally-extending gas ducts, said collecting electrodes each comprising a longitudinal row of pocket electrode elements having particle collecting surfaces defining'passageways open to the gas ducts and leading downwardly into said chamber, and longitudinally-extending bafiles in the lower portions ot said gas ducts, said bafiles each including two bafile walls slop ing downwardly in opposite directions from anapex located within the gas duct, toward the two adjacent collecting electrodes.

4. In an electrical precipitation apparatus for removing suspended particles from a gas, the combination comprising: a shell enclosing a. horizontal passageway for a stream of the gas, and formed with a material-collecting chamber below said horizontal gas passageway, vertical collecting electrodes extending longitudinally and spaced transversely 01 said gas passageway and defining longitudinally-extending gas ducts, said collecting electrodes each comprising a longitudinal row of pocket electrode elements having particle collecting surfaces defining passageways open to the gas ducts and leading downwardly into said chamber, and longitudinally-extending bailies in the lower portions-oi said gas ducts,- said baiiles each including two baiiie walls sloping downwardly in opposite directions from an apex located within. the gas duct, toward the two adjacent collecting electrodes, and substantially vertical wall portions depending from the lower edges or said sloping wall portions and positioned in juxtapositionto said collecting electrodes.

5. In an electrical precipitation apparatusibr removing suspended particles from -a gas, the combination comprising: a shell enclosing a horizontal passageway for a stream of the gas, and formed'with a material collecting chamber below said horizontal gas passageway, collecting electrode means in said passageway, and a plurality of transversely-spaced baiile walls extending longitudinally of said gas passageway arranged between said gas passageway and said materialcollecting chamber, said baiiie walls sloping in transverse planes, and wall members located at opposite ends of said longitudinally-extending "baiile walls substantially separating the materialcollecting chamber and the spaces between the zontal passageway for a stream of the gas, and formed with a material-collecting chamber below said horizontal gas passageway, vertical collecting electrodes extending longitudinally and spaced transversely of said gas passageway and defining longitudinally-extending gas ducts, a pair of horizontally-spaced longitudinally-extending baiiles at the bottom of each of said gas ducts, the bailies of each such pair having wall portions sloping downwardly toward one another to define relatively narrow longitudinally-extending slots for downward passage oi collected material, and closure means at each end of the longitudinally-extending bafiles blocking oil gas flow between the gas passageway and the material-collecting chamber by way of the spaces between the ends oi. the ba'files.

'7. In an electrical precipitationapparatus for removing suspended particles'from a gas, the combination comprising: a shell enclosing a horizontal passageway for a stream of the gas, and formed with a material-collecting chamber below said horizontal gas passageway, vertical collecting electrodes extending longitudinally and spaced transversely of said gas passageway and defining longitudinally-extending gas ducts, loncombination comprising: a shell enclosing a hori- I zontal passageway for a stream of the as, and

formed with a material-collecting. chamber be-' low said horizontal gas passageway, vertical colend portions of said bailie walls from said gas I passageway.

6.111 an electrical precipitation apparatus for removing suspended'particles from a gas, the

combination comprising: a shell enclosing a Q91}? lecting' electrodes extending longitudinally and spaced transversely of said gas passageway and defining longitudinally-extending gas ducts, said collecting electrodes each comprising a longitu dinal row of pocket electrode, elements having particle collecting surfaces defining passageways open to the gas ducts and leading downwardly into said chamber, a pair of horizontally-spaced, longitudinally-extending baiiles at the bottom of each or said gas ducts, the bafiles of each such 'pair having wall portions sloping downwardly toward one another to define relatively narrow longitudinally-xtending slots for downward pas,

sage oi collected material, and closure means at each end or the longitudinally-extending baffies blocking oil gas flow between the gas passageway and the material-collecting chamber by way oi the spaces between the ends of the batdinal row of pocket electrode elementshavin Particle collecting surfaces defining passageways open-to the gas ducts and leadingv downwardly into said chamber, longitudinally-extendingbaflongitudinally-extending gas ,ing electrodes each comprising a longitudinal viding a material-collecting chamber below said fies in the lowerportio of said gas ducts, said baiiies each including t o bafiie walls sloping downwardly in opposite directions from an apex located within the gas duct, toward the two adjacent collecting electrodes, and closure means at the ends of said longitudinally-extending baifies blocking of! gas now between the gas passageway and the material-collecting chamber by combination comprising: a shell enclosing ahorizontal passageway for a stream of the gas, and

formed with a material-collecting chamber below said horizontal gas passageway, vertical collecting electrodes extending longitudinally and spaced transversely of said gas passageway and defining ducts, said collectrow of pocket electrode elements having particle collecting-suriaces defining passageways open to I the gas ducts and leading downwardly into said passageway, and collecting electrode structures each comprising a plurality of vertically-extending elements positioned in a longitudinal row in said passageway and defining longitudinallyexeach of said elements comtending gas duc prising 'a vert al web member parallel to said gas ducts and a plurality of vertical web members projectingirom said parallel web member at an angle thereto into adjacent gas ducts to define vertically-extending passageways each open to only one of said gas ducts, each of said pro-'- jecting webmembers being inclined outwardly and iorwardlyin the direction of gas fiow through the gas duct into which the members project, said elements being longitudinally spaced chamber, longitudinally-extending bailles in the lower portionsoi 'said gas ductsf said baiiies each including two bai'iie walls sloping downwardly in opposite directions from an apex located within "formed with a material-collecting the gas duct. toward the two adjacent collecting electrodes. and wall members located at the two ends of said longitudinally-extending baiiles-separating the material-collecting chamber and the.

space between the two sloping walls of each baile from the gas passageway..

11.111 an electrizal precipitation apparatus roiremoving'suspend particles from. a gas. the

' combination comprising: a shell enclosing a horizontal passageway for a stream of gas and providing a material-collecting chamber below said eway, and collecting electrode structures each comprising a plurality of vertically-extending elements positioned in a longitudinal row in said passageway and defining longitudinally-extending gas ducts, each of said elements comprise ing a vertically-extending member parallel to said gas ducts and a plurality of vertically-extending members projecting from said parallel. member apart to provide vertical passages'connecting adjacent gas ducts through said collecting electrode structure. a

14. In an electrical precipitation apparatus for removing suspended particles from a .gas, the combination comprising: a shell enclosing a horizontal passageway for a stream of the gas, and

chamber below said horizontal gas passageway, verticalcollecting electrodes extending longitudinally and spaced transversely of said gas passageway and defining longitudinally-extending gas ducts, and a pair oi horizontally-spaced longitudinally-extending baiiies at the bottom of each of said gas ducts, the bafiies of each such D Thaving wall portions sloping downwardly from positions adjacent. the collecting sides of the corresponding duct toward one another to define between atively narrow longitudinally-extending slot located substantially centrally of such duct for downward passage of collectedmaterial.

transversely of said gas ducts to define at least 1 one vertically-extending eway open to only one 01' said gas ducts. said elements being longitudinally spaced apart to provide vertical PM? sages connecting adjacent gas ducts through said collecting electrode structure.

12. In an electrical precipitation apparatus for removing suspended particles from a gas, the

combination comprising: ,a shell enclosing a horiaontal eway for a stream of gas and providing a material-collecting chamber below said passageway, and collecting electrode structures each comprising a plurality oi vertically-extending elements positioned in]. longitudinal row in said passageway and defining longitudinally-extending gas ducts', each or said elements comgas ducts and a plurality of vertical web members projecting from said parallel web member into adjacent gas ducts to define vertically-extending passageways each open to only one of said gas ducts said elements being longitudinally spaced apart to provide vertical passages connecting adamt m ducts through saidcollecting electrode is. In an electricalprecipitation s paraiusior prising a vertical web member. parallel to said 15. In an electrical precipitation apparatus for removing suspended particles from a gas, the combination comprising: a shell enclosing a horizontal eway for a stream of the gas, and

formed with a material-collecting chamber be-,;

low said' horizontal gas eway, vertical coilecting electrodes extending longitudinally and spaced transversely defining longitudinally-extending gas ducts, and longitudinally-extending baiiies in the lower portions of said gas ducts, said bafiles each including two longitudinally-extending walls sloping downwardly in opposite directions from an apex extending longitudinally and substantially centrally oi the corresponding duct to positions adjacent the collecting electrodes at the respective sidesoi such duct,- and said'baiiies being spaced, transversely'to provide a longitudinally-extending slot at the bottom of each collecting electrode ior downward passage of collected material.

16. In an electrical precipitation apparatus for removing suspended particles from a gas. the

formed with a-niaterial-coliecting chamber below said horizontal gas passageway. vertical collecting electrodes extending longitudinally and spaced transversely of said gas. i and defining longitudinally-extending gas ducts, and ,longitudinallyextendina baiiles in the lower portions of said gas ing downwardly toward adjacent baiiies to define between the lower edges thereoi! relatiyely narelectrodes at the respective their lower edges a rel-- of said gas passageway and ducts having wall portions slop- 

